This application requests a supplement to funds previously awarded under grant R01 EY01075. Additional funds are needed because research in one of the originally proposed areas is proceeding faster than anticipated. This has both created an unexpected demand for supplies and raised a new research problem. The new research proposed here originates in the results of an autoradiographic study of the retina's cholinergic system. It asks whether or not the acetylcholine-synthesizing cells observed in the ganglion cell layer of the rabbit retina are in fact ganglion cells, and, if so, where they project. The question will be investigated by autoradiographic study of retinas whose ganglion cells have degenerated after optic nerve section; by an attempt to label the acetylcholine-synthesizing cells via retrograde transport in the optic nerve; and by analysis of the radioactive choline metabolites found in the lateral geniculate body and superior colliculus after intraocular injection of 3H-choline.